IHT100 is HMRC's set of Inheritance Tax accounts for chargeable events during someone's life or in a trust, rather than on death. There's a separate form for each event: IHT100a for a gift into trust where tax is due now, IHT100c for an exit charge, IHT100d for the 10 year anniversary and so on. You report the event, get a payment reference on IHT122 and pay within 6 months of the event.
Everything here comes from GOV.UK's IHT100 and Trusts and Inheritance Tax guidance and the IHT100a form, as of October 2026.
Which IHT100 form you need
| Chargeable event | Form |
|---|---|
| Gift or other transfer of value where tax is payable now, usually into a trust | IHT100a |
| A beneficiary's qualifying interest in possession ends during their lifetime | IHT100b |
| A qualifying interest in possession ends because someone died (trustees) | IHT100b (death), or IHT418 for executors |
| Assets leave a trust and stop being relevant property (exit charge) | IHT100c |
| Relevant property in the trust at a 10 year anniversary | IHT100d |
| Assets stop being held in a special trust | IHT100e |
| A conditional exemption ends | IHT100f |
| Assets stop being held in an 18 to 25 trust | IHT100h |
HMRC says to complete only the form for the event you're reporting. It also says to check whether the trust needs registering before you start.
The rates behind the forms
- Transfers into most trusts are taxed once the settlor's transfers, plus chargeable gifts in the previous 7 years, go over the £325,000 threshold. Tax on the excess is 20% if the trustees pay.
- If the settlor pays instead, the loss to their estate is bigger, so the tax goes up.
- If the settlor dies within 7 years, the estate pays a further 20%, bringing it to the full 40%.
- Exit charges on relevant property leaving a trust are charged at up to 6%.
- The 10 year anniversary charge is on the net value of relevant property the day before the anniversary, after debts and reliefs such as Business or Agricultural Relief.
These figures are as of October 2026 and come from the GOV.UK trusts guidance.
When there's no exit charge
Here's the timing detail trustees use most. HMRC lists occasions when no exit charge applies even to relevant property, including assets transferred out within 3 months of the trust being set up or within 3 months after a 10 year anniversary. It also excludes trustees' payments of costs and expenses, some capital payments where Income Tax is due, and excluded property such as some foreign assets.
What the IHT100a account asks for
IHT100a works with supplementary schedules. The ones you'll meet most:
- D31 if the transferor isn't domiciled in the UK, and D31a or D31b for the long-term UK residence rules
- D32 for stocks and shares
- D33 for loans owed to the transferor that are part of the event
- D34 for life insurance and annuities
- D36 for UK land and buildings
- D38 for deducting Business Relief
- D39 for assets outside the UK
Keep every document you used to fill in the forms and schedules. You don't send copies unless HMRC asks.
Paying, and what happens next
- Fill in IHT122 to get an Inheritance Tax payment reference, at least 3 weeks before you want to pay.
- Pay within 6 months after the chargeable event. Paying late means interest, and the IHT100a notes explain how to work it out.
- HMRC writes to confirm it has the form and gives a date you'll hear by if it has questions. No contact by that date means no questions.
- If the account is picked for a compliance check, HMRC writes within 12 weeks, and the Valuation Office Agency or Shares and Assets Valuation may check values.
When you don't need an IHT100
Exempt transfers don't need one, such as assets passing between spouses or civil partners after death or gifts to a registered UK charity. Estates on death use IHT400 instead, and gifts made in the 7 years before death are reported there on IHT403. Trusts can also bring Capital Gains Tax and Income Tax, so check whether the trustees need a Self Assessment return.
What counts as a transfer out of a trust
Trustees often don't realise an exit charge has happened. GOV.UK lists these as transfers out of trust:
- the trust comes to an end
- some of the assets are distributed to beneficiaries
- a beneficiary becomes entitled outright to enjoy an asset
- an asset becomes part of a special trust, such as a charitable trust or a trust for a disabled person, and stops being relevant property
- the trustees make a non-commercial transaction that reduces the value of the trust fund
Gifts where you keep a benefit
If you put something into a trust but keep using it, such as giving away your house and living in it, it's a gift with reservation of benefit. You pay 20% on the transfer into trust and the asset still counts in your estate. To stop double taxation, only the higher of the two charges is applied if you die, so the total never goes above 40%.
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The verdict
Identify the event first, because each IHT100 form covers one event only, then put the 3 month exit windows and the 10 year anniversary in the trust diary. Ask for the IHT122 reference early and pay within 6 months to avoid interest. The calculations for exit and anniversary charges are complex, and where a family home is held in a trust, HMRC suggests talking to a solicitor or other adviser who knows trust law.
Frequently asked questions
What is the IHT100 form?
It's the collection of HMRC forms used to report chargeable events on gifts and trusts when Inheritance Tax is due, with a separate form for each type of event.
When do I pay Inheritance Tax on an IHT100 event?
Within 6 months after the chargeable event, using a payment reference from form IHT122.
What is the rate on a gift into a trust?
20% on the value above the £325,000 threshold if the trustees pay, as of October 2026.
Which form reports a 10 year anniversary charge?
IHT100d, for assets that are relevant property immediately before each 10 year anniversary of the trust.
How long does HMRC take to start a compliance check?
HMRC writes within 12 weeks if your form has been selected for a compliance check.
Do I need an IHT100 for a gift to a charity?
No. Gifts to a registered UK charity are exempt from Inheritance Tax, so no IHT100 is needed for them.
